Chronology and geochemical composition of cassiterite and zircon from the Maodeng Sn-Cu deposit, Northeastern China: Implications for magmatic-hydrothermal evolution and ore-forming process

Primary tin deposits usually contain little or no copper due to the distinct geochemistry of Sn and Cu. However, examples copper-rich in many provinces around world are also well known. The genesis remains controversial. Maodeng Sn-Cu polymetallic, a typical Cu-rich deposit southern Great Xing’an Range (SGXR) Northeast China, offers an excellent opportunity reveal coupled copper-tin deposits. ore mineralization is associated with granite porphyry, complement phase Alubaogeshan complex, which emplaced into volcanic rocks Lower Permian Dashizhai Formation. Herein, we report new zircon cassiterite U-Pb ages their trace elements compositions, aim constraining metallogenic chronology framework, clarifying indicative effects ore-forming fluids on different stages, thus establishing genetic model for deposit. LA-ICP-MS dating from porphyry yields weighted mean age 134.6 ± 0.4 Ma, consistent (ca. 138 Ma) monzogranite (main complex) (137–140 Ma), suggesting Early Cretaceous under Paleo-Pacific plate slab roll-back setting. Granite displays more evolved characterisrics, higher SiO2 contents (71.5 ∼ 77.4 wt%), Rb/Sr ratios (3.39 10.33) lower Nb/Ta (10.86 13.06) compared those (SiO2 70.4 72.1 wt%; 1.03 1.72 13.34 15.83, respectively). This further supported by zircons monzogranite, because former has stronger Eu anomaly, Hf concentrations, Zr/Hf Th/U than latter. Our data, integrated previously published geochemical suggest that granites characterized oxygen fugacity, differential degree aluminum saturation index (ASI) Sn-W could use address have relatively small potential. cassiterites high Fe (up 3358 ppm), Ti 1894 ppm) abnormal In (∼2500 but low Nb, Ta contents. From early late stage, W U increased, process experienced cooling, increasing volatile fluid-rock reaction. Finally, was established, highlight oxidized exsolved upwelling mantle magma would add reduced, Sn-rich chambers. contribution indicate that, Cu metals come crustal granitic magma, respectively, likely product spatial coupling.